January Weather in Sullivan, United States

Last updated: June 24, 2025

In January, the average temperature in Sullivan, United States hovers around -1°C (30°F). Expect minimum temperatures to dip as low as -25°C (-12°F), while highs can reach up to 19°C (66°F). Over the month, 79 mm (3.1 in) of precipitation is likely, spread over 8 days. With an average humidity of 84%, be prepared for a chilly and damp atmosphere!

January Temperature in Sullivan

In January in Sullivan, the average temperature is -1°C (30°F). Maximum temperatures can reach 19°C (66°F), while the minimum can dip as low as -25°C (-12°F). It’s essential to pack accordingly and be prepared for a range of weather conditions when traveling to Sullivan during this time.

January Weather in Sullivan: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Sullivan, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Sullivan, January typically has an average temperature of -1°C (30°F), with highs reaching up to 19°C (66°F) and lows dropping to around -25°C (-12°F).

Data source: Temperature data for Sullivan generated using information from the Copernicus Climate Change Service.

January Precipitation in Sullivan

In Sullivan in January, the precipitation amount is 79 mm (3.1 in) during 8 days, indicating a relatively wet period for the area.

January Precipitation Trends in Sullivan

The chart displays monthly precipitation patterns in Sullivan, with values for each month alongside January’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how January’s conditions compare to those of other months. In Sullivan, January typically receives around 79 mm (3.1 inches) of precipitation spread over approximately 8 days.

Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

January Humidity in Sullivan

In Sullivan in January, humidity is 84%. With an average temperature of -1°C (30°F), this humidity feels like a sharp chill that seeps into your bones, making travel uncomfortable as the wetness in the air intensifies the cold, leaving you yearning for warmth and shelter.

January Average Humidity in Sullivan

This chart illustrates the average monthly humidity levels in Sullivan, with January’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In January, average humidity in Sullivan is approximately 84%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in Sullivan

In Sullivan in January, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Sullivan, you can check the information here.

Maximum UV Index Levels in Sullivan for January

The chart shows the monthly maximum UV Index (UVI) for Sullivan in January, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In January, the maximum UV index in Sullivan typically reaches 3, which falls under the moderate exposure category.

Data source: Sullivan January UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How January Weather in Sullivan Compares to Other Months

Weather in Sullivan varies notably across the year, with each month offering distinct climate conditions. This page compares January’s weather to other months in Sullivan, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Sullivan, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-1°C (30°F)	79 mm (3.1 inches)	84%	moderate
February Weather	0°C (33°F)	79 mm (3.1 inches)	82%	moderate
March Weather	7°C (44°F)	127 mm (5.0 inches)	84%	high
April Weather	12°C (53°F)	125 mm (4.9 inches)	83%	very high
May Weather	19°C (66°F)	138 mm (5.4 inches)	80%	very high
June Weather	24°C (76°F)	108 mm (4.2 inches)	83%	extreme
July Weather	25°C (78°F)	116 mm (4.6 inches)	82%	very high
August Weather	24°C (75°F)	128 mm (5.0 inches)	82%	very high
September Weather	22°C (71°F)	69 mm (2.7 inches)	79%	very high
October Weather	14°C (58°F)	123 mm (4.8 inches)	79%	high
November Weather	6°C (42°F)	89 mm (3.5 inches)	88%	moderate
December Weather	3°C (37°F)	64 mm (2.5 inches)	87%	moderate